Micron-sized grains may be damaged or destroyed during interstellar travel.
Conventional theoretical estimates of the lifetime of
interstellar dust particles are relatively short (\(\sim \)  0.1–1 Gyr, [1]}).
However, these estimates are highly uncertain, and such short lifetime
conflicts with the observed dust abundance and dust production time
scales in the Milky Way as well as distant galaxies
[2]}, [3]}, [4]}. About ten times longer lifetime
is then favorable, and some theoretical studies support this possibility
[5]}, [6]}. Furthermore,
micron-sized grains considered here are larger than the general
interstellar dust grains responsible for the extinction of light from astronomical objects
(5–250 nm, [7]}, [8]}).
Such large grains are decoupled from ISM gas and smaller grains, resulting in
a longer lifetime [8]}, [10]}, [11]}, [12]}.
Therefore, the interstellar lifetime of micron-sized grains, \(\tau _{is}\) ,
could be comparable with the age of the Solar System or
the Milky Way (\(\tau _{is} \sim \)  1–10 Gyr), though further studies are
necessary for a more quantitative estimate.
